• Advances in aircraft and spacecraft science
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• v.6 no.1
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• pp.1-18
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• 2019

This present article represents the study of the forced vibration of nanobeam of a single-walled carbon nanotube (SWCNTs) surrounded by a polymer matrix. The modeling was done according to the Euler-Bernoulli beam model and with the application of the non-local continuum or elasticity theory. Particulars cases of the local elasticity theory have also been studied for comparison. This model takes into account the different effects of the interaction of the Winkler's type elastic medium with the nanobeam of carbon nanotubes. Then, a study of the influence of the amplitude distribution and the frequency was made by variation of some parameters such as (scale effect ($e_0{^a}$), the dimensional ratio or aspect ratio (L/d), also, bound to the mode number (N) and the effect of the stiffness of elastic medium ($K_w$). The results obtained indicate the dependence of the variation of the amplitude and the frequency with the different parameters of the model, besides they prove the local effect of the stresses.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• no.1
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• pp.230-236
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• 2001

The usual definition of and urban resort was a place vastly different from places of daily life such as a theme park or other tourist destination. At the same time, revival of the combination of usual and unusual spaces, in a way like the mixed "Hare"(Special occasion of public event) and "Ke"(Daily life) spaces of communities of old Japan, is part of the idea of urban resorts. And they are places, which start by making a comfortable urban environment for citizens, providing a daily life full of culture and promoting a city′s identity to visitors. if we think about the kinds of structural elements of urban resorts, the usual elements include community, local culture and industry, while the unusual elements include symbols, festivities and interaction. Kobe Wing Stadium is a venue for the 2002 FIFA World Cup hosted by Korea and Japan. The city will build the stadium, but after construction management will be given over to private enterprise, hoping to utilize that sector′s business know how. A competition was held to determine the private executor who would be entrusted with the planning, design, construction and management of the project, considering the conditions of the area, the stadium′s relationship to it and local revitalization. The competition was won by a private enterprise (Kobe Steel Obayashi Group). The them of "Creation of a Sports Community Park" grapples with the large issue of the facility′s relationship with the community. American geographer Yi-fu Tuan coined the word "topophilia" to indicate love of a place. No other word could better describe the desired urban resort nature of the stadium. From this historical perspective it seems that stadiums have great potential as urban resorts. The factor that will determine their success is the attitude of citizens toward them, in short whether they develop topophilia for them or not. We examined the urban resort nature of Kobe Wing Stadium. Regarding daily life, we saw the attempts to revive the local community, the possibility of deepening the local culture and the weakened state of local industry. As a place that is for more than daily life, we saw the certainty of the stadium′s symbolism, its potential as a place for festivities and the test it will face as a space for interaction. Even though several issues are left for future resolution, evaluating Kobe Wing Stadium through these elements of an urban resort, it is clearly founded in the daily life of the community while providing a venue for "Hare"occasions. Fulfilling the roles of an urban resort, it provides many opportunities for local residents to enjoy their and gives visitors a reason to come repeatedly.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.493-498
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• 2008

We proposed "Table Mediator" which is a tabletop system for digital storytelling that uses web-retrieved information for the students' educational field trip. Students can perform their storytelling for their virtual pre-field trip to build up a sequential path as a story with web-retrieved documents, satellite images, geographical information, and group discussion. The proposed system was designed to lessen the limitation of individual interaction such as restricted viewpoint and biased inclination by group digital storytelling. Local interactions also have the limitation such as insufficient information and knowledge and the system supplied the rich live information such as subjective critiques or recently discovered history, or new updates for building a story that makes users arrange their own idea as a consistent story to lessen the limitation of the local interactions. The system can be used for various applications such as travel, education and other collaborative works with group interaction.

• Journal of KSNVE
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• v.10 no.4
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• pp.610-614
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• 2000

Cellular Automata(CA)s are used as a simple mathematical model to investigate self-organization in statistical mechanics, which are originally introduced by von Neumann and S. Ulam at the end of the 1940s. CAs provide a framework for a large class of discrete models with homogeneous interactions, which are characterized by the following fundamental properties: 1) CAs are dynamical systems in which space and time are discrete. 2) The systems consist of a regular grid of cells. 3) Each cell is characterized by a state taken from a finite set of states and updated synchronously in discrete time steps according to a local, identical interaction rule. 4) The state of a cell is determined by the previous states of a surrounding neighborhood of cells. A cellular automaton has been attracted wide interest in modeling physical phenomena, which are described generally, partial differential equations such as diffusion and wave propagation. This paper describes one and two-dimensional analysis of wave propagation phenomena modeled by CA, where the local interaction rules were derived referring to the Lattice Gas Model reported by Chen et al., and also including finite difference scheme. Modeling processes by using CA are discussed and the simulation results of wave propagation with one wave source are compared with that by finite difference method.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1186-1191
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• 2003

The 40% of wall criterion, which is generally used for the plugging of steam generator tubes, may be applied only to a single crack. In the previous study, a total of 9 failure models were introduced to estimate the local failure of the ligament between cracks and the optimum coalescence model of multiple collinear cracks was determined among these models. It is, however, known that parallel axial cracks are more frequently detected during an in-service inspection than collinear axial cracks. The objective of this study is to determine the plastic collapse model which can be applied to the steam generator tube containing two parallel axial through-wall cracks. Nine previously proposed local failure models were selected as the candidates. Subsequently interaction effects between two adjacent cracks were evaluated to screen them. Plastic collapse tests for the plate with two parallel through-wall cracks and finite element analyses were performed for the determination of the optimum plastic collapse model. By comparing the test results with the prediction results obtained from the candidate models, a plastic zone contact model was selected as an optimum model.

• Nuclear Engineering and Technology
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• v.36 no.4
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• pp.316-326
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• 2004

The $40\%$ of wall criterion, which is generally used for the plugging of steam generator tubes, is applied only to a single crack. In a previous study, a total number of 9 failure models were proposed to estimate the local failure of the ligament between cracks, and the optimum coalescence model of multiple collinear cracks was determined among these models. It is, however known that parallel axial cracks are more frequently detected than collinear axial cracks during an in-service inspection. The objective of this study is to determine the plastic collapse model that can be applied to steam generator tubes containing two parallel axial through-wall cracks. Three previously proposed local failure models were selected as the candidates. Subsequently, the interaction effects between two adjacent cracks were evaluated to screen them. Plastic collapse tests for the plate with two parallel through-wall cracks and finite element analyses were performed to determine the optimum plastic collapse model. By comparing the test results with the prediction results obtained from the candidate models, a COD base model was selected as an optimum model.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.3
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• pp.381-388
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• 2001

Presented are heat data which describe the effect of interaction between bulk flow pulsations and a vortex embedded in a turbulent boundary layer. The pulsation frequencies are 3 Hz, 15 Hz and 30 Hz. A half delta wing with the same height as the boundary layer thickness is used to generate the vortex flow. The convection heat transfer coefficients on a constant heat-flux surface are measured by embedded 77 T-type thermocouples. Spanwise profiles of convection heat transfer coefficients show that upwash region of vortex flow is influenced by bulk flow pulsations. The local heat transfer coefficient increases approximately by 7 percent. The increase in the local change of convection heat transfer coefficient is attributed to the spanwise oscillatory motion of vortex flow especially at the low Strouhal number and to the periodic change of vortex size.

• Nuclear Engineering and Technology
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• v.48 no.1
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• pp.72-86
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• 2016

A steam explosion may occur during a severe accident, when the molten core comes into contact with water. The pressurized water reactor and boiling water reactor ex-vessel steam explosion study, which was carried out with the multicomponent three-dimensional Eulerian fuel-coolant interaction code under the conditions of the Organisation for Economic Co-operation and Development (OECD) Steam Explosion Resolution for Nuclear Applications project reactor exercise, is presented and discussed. In reactor calculations, the largest uncertainties in the prediction of the steam explosion strength are expected to be caused by the large uncertainties related to the jet breakup. To obtain some insight into these uncertainties, premixing simulations were performed with both available jet breakup models, i.e., the global and the local models. The simulations revealed that weaker explosions are predicted by the local model, compared to the global model, due to the predicted smaller melt droplet size, resulting in increased melt solidification and increased void buildup, both reducing the explosion strength. Despite the lower active melt mass predicted for the pressurized water reactor case, pressure loads at the cavity walls are typically higher than that for the boiling water reactor case. This is because of the significantly larger boiling water reactor cavity, where the explosion pressure wave originating from the premixture in the center of the cavity has already been significantly weakened on reaching the distant cavity wall.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.125-132
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• 2019

Because the water exposed to shock waves caused by an underwater explosion cannot withstand the appreciable tension induced by the change in both pressure and velocity, the surrounding water is cavitated. This cavitating water changes the transferring circumstance of the shock loading. Three phenomena contribute to hull-plate damage; initial shock loading and its interaction with the hull plate, local cavitation, and local cavitation closure then shock reloading. Because the main concern of this paper is local cavitation due to a near-field underwater explosion, the water surface and the waves reflected from the sea bottom were not considered. A set of governing equations for the structure and the fluid were derived. A simple one-dimensional infinite plate problem was considered to verify this uncoupled solution approach compared with the analytic solution, which is well known in this area of interest. The uncoupled solution approach herein would be useful for obtaining a relatively high level of accuracy despite its simplicity and high computational efficiency compared to the conventional coupled method. This paper will help improve the understanding of fluid-structure interaction phenomena and provide a schematic explanation of the practical problem.

• The Journal of the Korea Contents Association
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• v.18 no.2
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• pp.450-458
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• 2018

The purpose of this study is to investigate the impact of university knowledge capital on the local business activity in the Korean local governments in the year 2015. We found that the increase of the standard deviation of university patent, scientific publications, incumbent firms, and industrial property rights raised the number of new knowledge-intensive firms to 15%, 11%, 54%, and 22%, respectively, in the local economy. In addition, the coefficient which reflects the interaction effects of the knowledge capital between universities and local industries was significant in the given area in the year. On the other hand, in the control variables, the coefficients for the size of local government, population density, and percentage of 20s~40s out of the total population in the local government were significant, showing above 90% level except for the variable of the distance between a local government and Seoul. In particular, when the knowledge capital of the university and industry coexists, the synergistic effect which has influence on the foundation of knowledge-intensive firms was meaningful despite the small scale, and these two types of knowledge capital could be complementary in creating new knowledge-intensive firms in the Korean local economy.